I'm as wondering if there was anyone out there with encough familiarity with the CCG and similar line of things to help me with the following.

I want to know if anyone can tell me if there are any rules of thumb or similar concerning hand sizes, deck sizes, and the proportional relationship between them, in customizable card games.

So the 5-card hand seems pretty common. It seems to me that this is merely because it is easy to hold, two gripped in each hand and the fith supported between them. But 7-hand games are easily possible as well - however that is easiest with playing cards, which are designed to be read from the corner only. So, any comments, observations or insights on an optimum practical hand size?

Does hand size have any effect on deck size? A full 7-card hand constitutes a greater proportion of the overall deck than a 5-card hand, assuming the same deck size. Is that a concern in any respect?

As someone who's been playing Magic: the Gathering for over ten years, I can say that proper card face design can go a long way. Once you reach a certain threshold of familiarity with the cards in a given game, you can use small elements of the card design to identify what you're holding even when you've got a huge hand, or a stack of cards with only the top centimeter showing.

You can determine probability using the following equation:

P = ( cT * xD ) / ( xT * cD ) , where cT is the number of cards you draw, cD is the number of cards in your deck, xT is the number of a certain kind of card you want to draw, and xT is the number of that same kind of card in your deck.

So, for a blackjack scenario, the chances of both cards being face cards or 10s in a 52 card deck are as follows:

P = ( 2 * 16 ) / ( 2 * 52 ) = 4 / 13 = almost 31% chance.

You can modify the formula to find values you need. If you've got, say, a 12-card deck and you want a 100% probability that you'll get at least one heart in your first five cards, the formula would look like so:

1 = ( 5 * xD ) / ( 1 * 12 )xD = 12 / 5 = 2.4

You'd need to include at least 3 hearts in your deck of 12 cards; that would make for 125% chance of drawing a heart. (That's no guarantee, but it's pretty likely that you'll get one most of the time.)